Here are five key takeaways from reporter Joanne Faryon’s newest story (which you can read by clicking here):

1. What’s Whooping Cough?

Whooping cough is a highly-contagious upper respiratory illness caused by the bacterium Bordetella pertussis. It’s sometimes called the “100 days’ cough.” In adults, it can mimic a bad cold, but in babies it can be deadly. The severe cough can produce an audible “whoop” sound when children catch their breath in between coughing spells.

According to the CDC, there are an estimated 16 million cases of pertussis and about 195,000 deaths per year.

2. We nearly wiped it out

Before mass immunization in the late 1940’s, whooping cough was a common cause of death in children. After a vaccine was developed, the rate of disease gradually declined to fewer than 5,000 cases reported nationally in 1968.

3. Now it’s coming back big time

The disease has been slowly making a comeback worldwide, but in 2010, it took California by storm when it killed 10 infants and made thousands of people sick. In 2014, four infants died and more than 10,000 people were diagnosed with whooping cough, the highest number in decades.

4. Scientists used to blame the parents, but now…

Scientists aren’t sure what is causing the outbreaks. In 2010, many public health officials and the media blamed people who refused to immunize their children. Now, research shows it’s likely several other factors: a change in vaccine in 1997; mutating and possibly more virulent strains; and better tools to diagnose the illness.

5. Vaccines are still better than nothing

Public officials say that while the vaccine has limitations, it’s better than not being immunized at all. It does provide some protection (studies show up to three years) and if you do get sick, your symptoms will be milder. Boosters in pregnant women can also protect their newborns.